Detecting resilience loss in ecosystems

Juan C. Rocha

slides: juanrocha.se/presentations/resilience_loss

resilience | rɪˈzɪlɪəns | (also resiliency)


noun [mass noun]

1 the capacity to recover quickly from difficulties; toughness: the often remarkable resilience of so many British institutions.
2 the ability of a substance or object to spring back into shape; elasticity: nylon is excellent in wearability, abrasion resistance and resilience.

The Oxford Dictionary

Resilience

The capacity of any system to absorb disturbance and reorganise while undergoing change so as to still retain essentially the same function, structure, feedbacks, and therefore identity

Folke, C. 2016. “Resilience (Republished).” Ecology and Society doi:10.5751/ES-09088-210444.

Resilience

• Henri Poincaré discovered bifurcations in 1886
• Bifucations (non-linear dynamics) are foundational to studies across natural, social sciences and humanities.
  E.g poverty traps, segregation, evolution of cooperation, cancer, language, finance, climate, the states of matter, among many others.
• In 1960-70s ecology: related to the meaning of stability and catastrophe theory
  (Lewontin, MacArthur, Holling, Ludwig, Walters, Noy-Meir, May)

Forest to savanna

Regime shifts are large, abrupt and persistence critical transitions in the function and structure of (eco)systems

Coral transitions

Regime shifts are large, abrupt and persistence critical transitions in the function and structure of (eco)systems

Fisheries collapse

Regime shifts are large, abrupt and persistence critical transitions in the function and structure of (eco)systems

Regime shifts history

Source: Jenn Burt PhD Thesis

Regime shifts

Very difficult to predict, and hard –sometimes impossible– to reverse

Andersen, J. et al. Trends Ecol Evol. (2009).

Abruptness affects the capacity to adapt to changes

Regime shifts and resilience

Scheffer at al 2001 Nature

Why are regime shifts important?

Where are regime shifts likely to happen?

Detecting resilience loss in ecosystems

Resilience indicators

Critical slowing down

Limitations: fail when dynamics are driven by stochastic processes or when signals have too much noise

Hastings & Wysham. 2010. Ecology Letters

Resilience indicators

Resilience indicators

Data

Analysis: one pixel

Muggeo VMR. Estimating regression models with unknown break-points. Stat Med. 2003;22(19):3055–71.

Gross primary productivity Terrestrial ecosystem respiration

~30% of ecosystem show symptoms of resilience loss, boreal forest and tundra particularly strong signals

LAI pick up strong signals on desertic and xerophitic biomes

Temporal coherence

Break points not only cluster in space, also in time!

Next steps

Research frontiers

Resilience is affected by the patterns of connections

Steffen et al 2018 PNAS

Lenton et al 2019 Nature

Cascading effects

~45% of the regime shift couplings analyzed present structural dependencies in the form of one-way interactions for the domino effect or two-way interactions for hidden feedbacks

Rocha, J. et al 2018. Science .

Conclusions

1. Ecosystems around the world are showing symptoms of resilience loss
   Up to ~30% as proportion of area
   

2. Boreal forest and tundra showing particularly strong early warning signals
   

3. While elusive, resilience can be approximated from data
   Critical slowing down | slow forcing: basin wider and less depth
   Critical speeding up | stochastic forcing: basin narrows
   Fractal dimension | loss of adaptive capacity

4. Research frontier: Can regime shifts be interconnected?
   Yes, not only through climate, but empirical evidence is missing (Rocha et al 2018. Science)

Tack | Gracias

Questions?


email: juan.rocha@su.se
twitter: @juanrocha
slides: juanrocha.se/presentations/resilience_loss
preprint: coming soon!

Stockholm Resilience Centre
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